2-Alkyl-1-naphthol-4-sulfonic acids

ABSTRACT

Compounds of the formula ##STR1## wherein R is alkyl of 11 to 14 carbon atoms, and X is --SO 3  H, --NO 2  or --SO 2  Cl 
     Are useful intermediates in the preparation of naphthoquinone miticides.

BACKGROUND OF THE INVENTION

This invention relates to 2-alkyl-1-naphthol derivatives which areuseful in the preparation of naphthoquinone miticides. The miticides areknown compounds described in German Pat. application No. 2,520,739. Thecompounds of this invention provide an economical route to the synthesisof the miticides which were previously synthesized by a completelydifferent and less efficient process. See U.S. Pat. Nos. 2,553,647 and2,553,648.

Salts of alkyl naphthol sulfonic acid have been mentioned in the art.U.S. Pat. No. 2,872,368 describes compounds of the formula ##STR2##wherein M is calcium or magnesium,

R is hydrogen, methyl or hydroxyl, and

(Alkyl)_(n) is 1-3 alkyl radicals containing 8-18 carbon atoms.

This patent describes no specific isomers and does not provide anymethod for preparation of these compounds.

SUMMARY OF THE INVENTION

Compounds of the formula ##STR3## wherein R is alkyl of 11 to 14 carbonatoms, and

X is --NO₂, --SO₃ H or --SO₂ Cl are novel compounds useful asintermediates in the preparation of naphthoquinone miticides. Becausethe most active of the miticides is the dodecyl substitutednaphthoquinone, the compounds of the above formula where R is alkyl of12 carbon atoms are preferred. Preferred for their ease of synthesis arecompounds of the above formula where X is --SO₃ H or --SO₂ Cl. Mostpreferred is 2-dodecyl-1-naphthol-4-sulfonic acid.

DETAILED DESCRIPTION OF THE INVENTION

The preparation of the compounds of this invention begins with anappropriate 2-higher alkyl-1-naphthol, which can be prepared by themethods taught by K. Nakanishi and L. F. Fieser, J. Amer. Chem. Soc.,74, 3910 (1952) and G. Fawaz and L. F. Fieser, J. Amer. Chem. Soc., 72,996 (1950). The reaction of an appropriate 2-higher alkyl-1-naphtholwith sulfuric acid, chlorosulfonic acid, or nitric acid at 25° over aperiod of several minutes to one hour affords the corresponding sulfonicacid, sulfonyl chloride, or nitro compound. ##STR4## where R is alkyl of11 to 14 carbon atoms and X is --SO₃ H, --SO₂ Cl, or --NO₂. The molarratio of the 2-higher alkyl-1-naphthol to the acid HOX is preferably inthe range of 1:1 to 1:3. Generally, an excess of the acid is employed toobtain higher yields of the desired product. The reactions are mostconveniently run at ambient temperature over a period of a few minutesto 1 hour. However, the reaction mixture may be heated to hasten therate of reaction or cooled to moderate the rate of reaction. Thereactions can be run without solvent; or, an inert organic solvent suchas dichloromethane, ether, chlorobenzene, acetic acid, or chloroform canbe employed to obtain a homogeneous reaction mixture or so that theproduct precipitates from the reaction mixture.

The compounds of this invention can be used to prepare 2-higheralkyl-3-hydroxy-1,4-naphthoquinone carboxylic acid esters by thefollowing representative procedure: ##STR5##

The naphthoquinone compounds of the formula ##STR6## and their use asmiticides in agriculture are described in German Pat. application No.2,520,739. Of these compounds, the compound where R is dodecyl ispreferred.

The following examples further illustrate this invention. All parts areby weight and temperatures are in degrees centigrade.

EXAMPLE 1 Preparation of 2-n-Dodecyl-1-naphthol-4-sulfonic Acid

A solution of 90 parts of sulfuric acid and 670 parts of dichloromethanewas added in one portion to a solution of 100 parts of2-n-dodecyl-1-naphthol and 670 parts of dichloromethane at ambienttemperature. After 10 minutes, the mixture was filtered and theprecipitate was washed three times with 670 parts of dichloromethane anddried to yield 111 parts of 2-n-dodecyl-1-naphthol-4-sulfonic acid, m.p.127°-130° C.

EXAMPLE 2 Preparation of 2-n-Dodecyl-1-naphthol-4-sulfonyl Chloride

A solution of 18 parts of chlorosulfonic acid in 67 parts ofdichloromethane was added to a solution of 7 parts of2-n-dodecyl-1-naphthol in 67 parts of dichloromethane in one portion atambient temperature. The resulting mixture was refluxed for 5 minutes,permitted to stand for 1 hour, and then poured into 100 parts of icewater. The dichloromethane was separated, washed with two 100-partportions of brine, dried with anhydrous magnesium sulfate and evaporatedto afford 5 parts of the oily 2-n-dodecyl-1-naphthol-4-sulfonylchloride, n_(D) ²⁵ = 1.556.

EXAMPLE 3 Preparation of 2-n-Dodecyl-4-nitro-1-naphthol

To a solution of 50 parts of 2-n-dodecyl-1-naphthol in 500 parts ofglacial acetic acid was added 28 parts of nitric acid (specific gravity1.4). The solution was stirred at ambient temperature for 1 hour andthen poured into 2,000 parts of water. The resulting mixture wasextracted with 1,400 parts of ether. The ether layer was separated;washed once with water (2,000 parts), twice with 10% aqueous sodiumbicarbonate solution (2,000 parts), and finally with water (2,000parts). The ether solution was dried with anhydrous magnesium sulfateand evaporated to afford 56 parts of 2-n-dodecyl-4-nitro-1-naphthol as aviscous yellow oil, n_(D) ²⁵ = 1.5454, which slowly crystallized to awaxy yellow solid on standing.

By the general procedures of Examples 1, 2 or 3, the following compoundscan be prepared:

2-n-undecyl-1-naphthol-4-sulfonic acid

2-n-tridecyl-1-naphthol-4-sulfonic acid

2-n-tetradecyl-1-naphthol-4-sulfonic acid

2-n-undecyl-4-nitro-1-naphthol

2-n-tridecyl-4-nitro-1-naphthol

2-n-tetradecyl-4-nitro-1-naphthol

2-n-undecyl-1-naphthol-4-sulfonyl chloride

2-n-tridecyl-1-naphthol-4-sulfonyl chloride

2-n-tetradecyl-1-naphthol-4-sulfonyl chloride

EXAMPLE 4 Use of 2-n-Dodecyl-1-naphthol-4-sulfonic Acid in thePreparation of 3-Acetoxy-2-n-dodecyl-1,4-naphthoquinone A. Preparationof 3-Chloro-2-n-dodecyl-1,4-naphthoquinone

A mixture of 6.3 parts of 2-n-dodecyl-1-naphthol-4-sulfonic acid, 100parts of acetic acid, 18 parts of water, 21 parts of sulfuric acid, and1 part of ferric chloride hexahydrate was cooled to 20°. Chlorine (3.1parts) was added to this mixture with vigorous stirring. The temperaturerose to 35° and the mixture turned yellow. The mixture was heated to 95°over 15 minutes and the temperature of the reaction mixture wasmaintained at 95° to 100° for 1 hour. Thirty parts of water were addedand the mixture was then cooled to 25° with vigorous stirring. The crudeproduct, which separated as brown granules, was filtered off and washedthree times with water (25 parts), twice with 10% aqueous sodiumbicarbonate (25 parts), twice with water (25 parts), twice with coldethanol (8 parts), and twice with cold hexane (7 parts), to afford 5parts of 3-chloro-2-n-dodecyl-1,4-naphthoquinone, m.p. 85°-87° C.

B. Preparation of 2-n-Dodecyl-3-hydroxy-1,4-naphthoquinone

A mixture of 10 parts of 3-chloro-2-n-dodecyl-1,4-naphthoquinone. 5parts of 50% aqueous sodium hydroxide and 320 parts of 95% aqueousethanol were heated at reflux for 15 minutes. The color of the mixtureturned from yellow to dark red. The mixture was cooled to 25° andacidified with 10% aqueous hydrochloric acid. The color of the mixturewas golden yellow after acidification. The product was filtered off andwashed twice with water (25 parts) and twice with cold methanol (25parts) to yield 8 parts of 2-n-dodecyl-3-hydroxy-1,4-naphthoquinone, mp.85° - 87° C.

C. A mixture of 2-Acetoxy-2-n-dodecyl-1,4-naphthoquinone

A mixture of 2.0 parts of 2-n-dodecyl-3-hydroxyl-1,4-naphthoquinone,0.81 parts of triethylamine, 0.63 parts of acetyl chloride and 50 partsof methylene chloride was stirred at room temperature for 30 hours. Theresulting mixture was distributed between methylene chloride and water.The methylene chloride layer was separated, dried over magnesiumsulfate, then filtered and evaporated under reduced pressure. Theresidue was crystallized from petroleum ether (b.p. 30°-60° C.) to give1.2 parts of 3-acetoxy-2-n-dodecyl-1,4-naphthoquinone, m.p. 57°-58° C.

I claim:
 1. A compound of the formula ##STR7## wherein R is alkyl of 11to 14 carbon atoms, andX is --SO₃ H.
 2. A compound of claim 1 wherein Ris alkyl of 12 carbons.